US4254071A - Method of preparing electrostatic coating compositions containing an epoxy resin - Google Patents
Method of preparing electrostatic coating compositions containing an epoxy resin Download PDFInfo
- Publication number
- US4254071A US4254071A US05/970,249 US97024978A US4254071A US 4254071 A US4254071 A US 4254071A US 97024978 A US97024978 A US 97024978A US 4254071 A US4254071 A US 4254071A
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- United States
- Prior art keywords
- premix
- weight
- resin
- coating
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title claims abstract description 16
- 239000003822 epoxy resin Substances 0.000 title claims description 6
- 229920000647 polyepoxide Polymers 0.000 title claims description 6
- 239000008199 coating composition Substances 0.000 title abstract description 4
- 238000009503 electrostatic coating Methods 0.000 title 1
- 238000000576 coating method Methods 0.000 claims abstract description 26
- 239000011248 coating agent Substances 0.000 claims abstract description 21
- 230000018044 dehydration Effects 0.000 claims abstract description 5
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 5
- 239000003795 chemical substances by application Substances 0.000 claims description 17
- 239000000843 powder Substances 0.000 claims description 15
- 238000001125 extrusion Methods 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 11
- DHKHKXVYLBGOIT-UHFFFAOYSA-N 1,1-Diethoxyethane Chemical compound CCOC(C)OCC DHKHKXVYLBGOIT-UHFFFAOYSA-N 0.000 claims description 5
- 229920002554 vinyl polymer Polymers 0.000 claims description 5
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 claims description 4
- RCHKEJKUUXXBSM-UHFFFAOYSA-N n-benzyl-2-(3-formylindol-1-yl)acetamide Chemical compound C12=CC=CC=C2C(C=O)=CN1CC(=O)NCC1=CC=CC=C1 RCHKEJKUUXXBSM-UHFFFAOYSA-N 0.000 claims description 4
- 239000011354 acetal resin Substances 0.000 claims description 3
- 229920006324 polyoxymethylene Polymers 0.000 claims description 3
- 239000011342 resin composition Substances 0.000 claims description 3
- 150000001241 acetals Chemical class 0.000 claims description 2
- 150000008065 acid anhydrides Chemical class 0.000 claims description 2
- 238000000227 grinding Methods 0.000 claims description 2
- 150000002902 organometallic compounds Chemical class 0.000 claims description 2
- 239000011347 resin Substances 0.000 claims description 2
- 229920005989 resin Polymers 0.000 claims description 2
- 239000004593 Epoxy Substances 0.000 claims 2
- 238000001816 cooling Methods 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 claims 1
- 239000008240 homogeneous mixture Substances 0.000 claims 1
- -1 phenol aldehyde Chemical class 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 abstract description 14
- 239000003054 catalyst Substances 0.000 abstract 1
- 238000001723 curing Methods 0.000 description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- CHJMFFKHPHCQIJ-UHFFFAOYSA-L zinc;octanoate Chemical compound [Zn+2].CCCCCCCC([O-])=O.CCCCCCCC([O-])=O CHJMFFKHPHCQIJ-UHFFFAOYSA-L 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 230000009257 reactivity Effects 0.000 description 3
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 238000006460 hydrolysis reaction Methods 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000001464 adherent effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 230000009931 harmful effect Effects 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000013008 moisture curing Methods 0.000 description 1
- 125000005474 octanoate group Chemical group 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
- IPCXNCATNBAPKW-UHFFFAOYSA-N zinc;hydrate Chemical compound O.[Zn] IPCXNCATNBAPKW-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
- H01B13/06—Insulating conductors or cables
- H01B13/065—Insulating conductors with lacquers or enamels
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D163/00—Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
Definitions
- Insulating coating compositions for applying to transformer wire are disclosed in commonly assigned U.S. patent applications Ser. Nos. 697,838 now abandoned and 889,889.
- the electrically insulating coating materials disclosed in the aforementioned applications comprise the reaction product of a mixture of polyvinyl acetal, phenol aldehyde resin and epoxy resin in a particular range of proportions. The mixture is formed into a powder for applying to wire without the use of solvents. The coated wire is then heated to cure and harden the applied coating.
- the aforementioned resin composition requires the addition of a prescribed amount of a curing agent which is designed to react and harden the coating into a tough flexible adherent layer during a thermally controlled coating process.
- the premixed powder including the curing agent is electrostatically applied to wire which is then heated to cause the resin composition to react with the curing agent.
- a preferred method of manufacturing the powder described in the above patent applications is to preblend the ingredients at room temperature and then to pass this premix through an extruder in order to prepare a homogeneous blend.
- the extruder will be operated at a temperature of 125° to 150° C.
- the extrudate is cooled and chopped into small granules which are subsequently ground to a fine powder of suitable particle size distribution.
- the ingredients of the premix will normally contain moisture which has been adsorbed from the atmosphere. It has been discovered that when such a premix containing moisture is passed through the heated extruder excessive loss of curing activity takes place, presumably by reaction of the curing agent with water, rendering it nonactive. The resultant powder when applied to wire does not produce a coating having the desired properties, specifically it is lacking in flexibility. If on the other hand the premix is dried prior to extrusion a much smaller loss of reactivity takes place and the resultant powder produces a coating having the desired properties including flexibility.
- the amount of water present in the undried premix and the harmful effect will depend on the atmospheric relative humidity. It has been discovered that the moisture content may commonly be as high as 2.5% and it must be reduced to less than 0.5% to produce satisfactory coatings.
- Insulating coating premixes for wire coatings are dehydrated prior to extrusion mixing to prevent a reaction between the curing agent and adsorbed moisture.
- the coating consisting of 25%-65% polyvinyl acetal resin, 10%-40% phenol aldehyde resin, 7%-60% epoxy resin and including about 0.5% curing agent is evacuated to remove any moisture in excess of 0.5% by weight.
- the dehydrated coating composition results in coated transformer wire having excellent flexibility.
- FIG. 1 is a graphic representation of the exothermic reaction rate at a temperature of 200° C., of the undried premix composition as a function of time, before and after extrusion;
- FIG. 2 is a graphic representation of the corresponding exothermic reaction rate of the coating premix before and after extrusion for a dehydrated premix in accordance with the invention.
- the coating premix was prepared in the manner described in the aforementioned U.S. patent applications wherein approximately 44 parts polyvinyl acetal resin, 20 parts phenol aldehyde resin, 26 parts epoxy resin with 0.50 parts of zinc octoate curing agent were mixed together to form the premix. Room temperature ambient conditions, temperature and relative humidity were noted at 25° C. and 50% respectively, and the moisture content of the premix was determined to be 2.2% under these ambient conditions. The calorimetric measurements were taken at 200° C. to determine the rate of the exothermic cure reaction. The exothermic reaction rate for the premix is shown at A in FIG. 1 before being extruded to mix the premix into a homogeneous composition.
- the premix is forced through a twin screw extruder where it is homogeneously combined when heated to approximately 150° C.
- the exothermic reaction is shown at B in FIG. 1 after extrusion. It is to be noted that the catalytic activity, as determined by the difference in exothermic reaction rate before and after extrustion, is substantially less after the extrusion process. It is presumed that the zinc octoate curing agent partially reacted with the adsorbed moisture within the premix so that less curing agent was available for curing the resin in the final coating process.
- the extrudate is then ground into a powder for applying to the wire.
- moisture and "water” are used interchangeably in order to describe the effect of moisture.
- a second premix was dehydrated by evacuation at room temperature for 24 hours. Moisture determinations were made by weighing prescribed amounts of the coating premix before and after dehydration. As discussed earlier, the coating premix which contained 2.2% by weight adsorbed water before dehydration measured a 0.5% moisture content in the dried premix.
- the exothermic reaction rate occuring in the dehydrated premix is shown at C in FIG. 2.
- the exothermic reaction rate for the same dehydrated premix after the heated extrusion process is shown at D for comparison purposes. It is readily noted that the difference in reactivity of the product can be estimated by the difference in energy peaks between samples D in FIG. 2 and B in FIG. 1 and that the dehydration process substantially improves the reactivity.
- the powders prepared from premixes having 0.5% and 2.2% moisture content were electrostatically applied to separate wires and flexibility measurements were taken on the coated wires. It was then observed that the wires coated with the powder from the dehydrated premix exhibited greater flexibility than the wires coated with powder from premix containing 2.2% moisture content.
- the method for dehydrating the coating premix comprises evacuation at room temperature for a time increment of approximately 24 hours, it is to be well understood that shorter evacuation times and higher evacuation temperatures, within the range of from 25° C. to 125° C., can be employed providing the temperatures employed do not approach the reaction temperature between the moisture and the curing agent.
- the dehydrated premix is disclosed for use with transformer wire this is by the way of example only.
- the insulating coating of the invention can be employed wherever insulating coatings are required.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Organic Insulating Materials (AREA)
Abstract
Insulating coating compositions for electrical wire are prepared by a method which includes a dehydration process to prevent any reaction from occurring between adsorbed moisture and the catalyst before the coating is electrostatically applied to the transformer wire.
Description
Insulating coating compositions for applying to transformer wire are disclosed in commonly assigned U.S. patent applications Ser. Nos. 697,838 now abandoned and 889,889. The electrically insulating coating materials disclosed in the aforementioned applications comprise the reaction product of a mixture of polyvinyl acetal, phenol aldehyde resin and epoxy resin in a particular range of proportions. The mixture is formed into a powder for applying to wire without the use of solvents. The coated wire is then heated to cure and harden the applied coating.
The aforementioned resin composition requires the addition of a prescribed amount of a curing agent which is designed to react and harden the coating into a tough flexible adherent layer during a thermally controlled coating process. The premixed powder including the curing agent is electrostatically applied to wire which is then heated to cause the resin composition to react with the curing agent.
A preferred method of manufacturing the powder described in the above patent applications is to preblend the ingredients at room temperature and then to pass this premix through an extruder in order to prepare a homogeneous blend. Typically, the extruder will be operated at a temperature of 125° to 150° C. The extrudate is cooled and chopped into small granules which are subsequently ground to a fine powder of suitable particle size distribution.
The ingredients of the premix will normally contain moisture which has been adsorbed from the atmosphere. It has been discovered that when such a premix containing moisture is passed through the heated extruder excessive loss of curing activity takes place, presumably by reaction of the curing agent with water, rendering it nonactive. The resultant powder when applied to wire does not produce a coating having the desired properties, specifically it is lacking in flexibility. If on the other hand the premix is dried prior to extrusion a much smaller loss of reactivity takes place and the resultant powder produces a coating having the desired properties including flexibility.
The amount of water present in the undried premix and the harmful effect will depend on the atmospheric relative humidity. It has been discovered that the moisture content may commonly be as high as 2.5% and it must be reduced to less than 0.5% to produce satisfactory coatings.
Insulating coating premixes for wire coatings are dehydrated prior to extrusion mixing to prevent a reaction between the curing agent and adsorbed moisture. The coating consisting of 25%-65% polyvinyl acetal resin, 10%-40% phenol aldehyde resin, 7%-60% epoxy resin and including about 0.5% curing agent is evacuated to remove any moisture in excess of 0.5% by weight. The dehydrated coating composition results in coated transformer wire having excellent flexibility.
FIG. 1 is a graphic representation of the exothermic reaction rate at a temperature of 200° C., of the undried premix composition as a function of time, before and after extrusion; and
FIG. 2 is a graphic representation of the corresponding exothermic reaction rate of the coating premix before and after extrusion for a dehydrated premix in accordance with the invention.
In order to determine the nature and extent of the moisture-curing agent reaction, a series of calorimetric analyses were performed on the wire coating premix before and after extrusion mixing. The coating premix was prepared in the manner described in the aforementioned U.S. patent applications wherein approximately 44 parts polyvinyl acetal resin, 20 parts phenol aldehyde resin, 26 parts epoxy resin with 0.50 parts of zinc octoate curing agent were mixed together to form the premix. Room temperature ambient conditions, temperature and relative humidity were noted at 25° C. and 50% respectively, and the moisture content of the premix was determined to be 2.2% under these ambient conditions. The calorimetric measurements were taken at 200° C. to determine the rate of the exothermic cure reaction. The exothermic reaction rate for the premix is shown at A in FIG. 1 before being extruded to mix the premix into a homogeneous composition.
During the extrusion process the premix is forced through a twin screw extruder where it is homogeneously combined when heated to approximately 150° C. The exothermic reaction is shown at B in FIG. 1 after extrusion. It is to be noted that the catalytic activity, as determined by the difference in exothermic reaction rate before and after extrustion, is substantially less after the extrusion process. It is presumed that the zinc octoate curing agent partially reacted with the adsorbed moisture within the premix so that less curing agent was available for curing the resin in the final coating process. The nature of the reaction between zinc octoate and water is not at this time well understood but is believed to involve the hydrolysis of the zinc octoate to zinc oxide which is noncatalytic for the reaction. Other curing agents such as acid anhydrides and other organometallic compounds besides metal octoates are expected to exhibit the same hydrolysis reaction.
After the thermal extrusion mixing process the extrudate is then ground into a powder for applying to the wire.
for purposes of this disclosure the terms "moisture" and "water" are used interchangeably in order to describe the effect of moisture. A second premix was dehydrated by evacuation at room temperature for 24 hours. Moisture determinations were made by weighing prescribed amounts of the coating premix before and after dehydration. As discussed earlier, the coating premix which contained 2.2% by weight adsorbed water before dehydration measured a 0.5% moisture content in the dried premix.
The exothermic reaction rate occuring in the dehydrated premix is shown at C in FIG. 2. The exothermic reaction rate for the same dehydrated premix after the heated extrusion process is shown at D for comparison purposes. It is readily noted that the difference in reactivity of the product can be estimated by the difference in energy peaks between samples D in FIG. 2 and B in FIG. 1 and that the dehydration process substantially improves the reactivity.
After extrusion and grinding, the powders prepared from premixes having 0.5% and 2.2% moisture content were electrostatically applied to separate wires and flexibility measurements were taken on the coated wires. It was then observed that the wires coated with the powder from the dehydrated premix exhibited greater flexibility than the wires coated with powder from premix containing 2.2% moisture content.
Comparisons between the coated wire flexibility determinations made from coating premixes having differing water content revealed that the flexibility of the coated wire is strongly effected by the quantity of water adsorbed in the coating premix. For rectangular cross section transformer wire the flexibility test consisted in providing a 90 degree edge bend to the wire after the wire was subjected to a 15% stretch. The coating must remain intact after the 90 degree bend in order to successfully pass the flexibility test. Wires experiencing cracks of the coating failed the flexibility test.
Wire coated with powder prepared from the dried premixes consistently passed the flexibility test whereas wire coated from powders prepared from premixes with a high moisture content failed the test.
Attempts to compensate for loss of curing agent activity by increasing the amount of curing agent in the undried premixes were unsuccessful since the extra curing agent produced powder having unsatisfactory flowout characteristics on the wire.
Although the method for dehydrating the coating premix comprises evacuation at room temperature for a time increment of approximately 24 hours, it is to be well understood that shorter evacuation times and higher evacuation temperatures, within the range of from 25° C. to 125° C., can be employed providing the temperatures employed do not approach the reaction temperature between the moisture and the curing agent.
Although the dehydrated premix is disclosed for use with transformer wire this is by the way of example only. The insulating coating of the invention can be employed wherever insulating coatings are required.
Claims (7)
1. A method for preparing an insulating coating for electrostatic powder application comprising the steps of:
preparing a coating premix consisting of a composition of resins including an epoxy resin and a curing agent selected from the group consisting of acid anhydrides and organometallic compounds
dehydrating the premix by heating within a first temperature range of from 25° C. to 125° C. to remove any moisture contained therein;
extruding the dehydrated premix through an extruder at a temperature range of 125° C. to 150° C. for providing a homogeneous mixture;
cooling the extruded mixture; and
grinding the extruded mixture into a powder.
2. The method of claim 1 wherein the resin composition comprises a mixture of polyvinyl acetal resin and phenol aldehyde resin with said epoxy resin.
3. The method of claim 1 wherein the polyvinyl acetal comprises 25%-65% by weight, the phenol aldehyde comprises 10%-40% by weight and the epoxy comprises 7%-60% by weight.
4. The method of claim 1 wherein the epoxy curing agent comprises from 0.10% to 1.00% by weight of the composition.
5. The method of claim 1 wherein the step of dehydration includes evacuating the premix.
6. The method of claim 1 wherein the extrusion comprises passing the composition through a twin screw extruder.
7. The method of claim 1 wherein the premix is dehydrated to a moisture content of less than 0.5% by weight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/970,249 US4254071A (en) | 1978-12-18 | 1978-12-18 | Method of preparing electrostatic coating compositions containing an epoxy resin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/970,249 US4254071A (en) | 1978-12-18 | 1978-12-18 | Method of preparing electrostatic coating compositions containing an epoxy resin |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US4254071A true US4254071A (en) | 1981-03-03 |
Family
ID=25516649
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US05/970,249 Expired - Lifetime US4254071A (en) | 1978-12-18 | 1978-12-18 | Method of preparing electrostatic coating compositions containing an epoxy resin |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US4254071A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4839444A (en) * | 1986-12-29 | 1989-06-13 | Essex Group, Inc. | High solids enamel |
| US6436326B1 (en) | 1999-06-15 | 2002-08-20 | Dow Global Technologies Inc. | Forming slurry of reactive components and continuously feeding into continuous reactor |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3239598A (en) * | 1961-04-04 | 1966-03-08 | Anaconda Wire & Cable Co | Polyvinyl acetal resin together with an epoxy resin and a resin selected from urea formaldehyde, melamine, and phenol formaldehyde coated on an insulated wire and method for producing the same |
| US3923947A (en) * | 1970-10-28 | 1975-12-02 | Du Pont | Process for continuously preparing extrudable, crosslinkable polyethylene compositions |
| US3932689A (en) * | 1973-10-13 | 1976-01-13 | Sumitomo Bakelite Company, Limited | Flexible adhesive composition and method for utilizing same and article formed therefrom |
| US3936522A (en) * | 1972-08-24 | 1976-02-03 | Buss, A.G. | Process for the preparation of intermediates of polyaddition and polycondensation resins |
| US4009224A (en) * | 1975-08-11 | 1977-02-22 | Minnesota Mining And Manufacturing Company | Epoxy resin powder including ethylene vinyl acetate |
| US4072795A (en) * | 1974-05-08 | 1978-02-07 | Westinghouse Electric Corp. | Thin film electrostatic epoxy powder coating process and the resulting article |
| US4088809A (en) * | 1976-02-25 | 1978-05-09 | Westinghouse Electric Corp. | Low dissipation factor electrostatic epoxy wire coating powder |
-
1978
- 1978-12-18 US US05/970,249 patent/US4254071A/en not_active Expired - Lifetime
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3239598A (en) * | 1961-04-04 | 1966-03-08 | Anaconda Wire & Cable Co | Polyvinyl acetal resin together with an epoxy resin and a resin selected from urea formaldehyde, melamine, and phenol formaldehyde coated on an insulated wire and method for producing the same |
| US3923947A (en) * | 1970-10-28 | 1975-12-02 | Du Pont | Process for continuously preparing extrudable, crosslinkable polyethylene compositions |
| US3936522A (en) * | 1972-08-24 | 1976-02-03 | Buss, A.G. | Process for the preparation of intermediates of polyaddition and polycondensation resins |
| US3932689A (en) * | 1973-10-13 | 1976-01-13 | Sumitomo Bakelite Company, Limited | Flexible adhesive composition and method for utilizing same and article formed therefrom |
| US4072795A (en) * | 1974-05-08 | 1978-02-07 | Westinghouse Electric Corp. | Thin film electrostatic epoxy powder coating process and the resulting article |
| US4009224A (en) * | 1975-08-11 | 1977-02-22 | Minnesota Mining And Manufacturing Company | Epoxy resin powder including ethylene vinyl acetate |
| US4088809A (en) * | 1976-02-25 | 1978-05-09 | Westinghouse Electric Corp. | Low dissipation factor electrostatic epoxy wire coating powder |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4839444A (en) * | 1986-12-29 | 1989-06-13 | Essex Group, Inc. | High solids enamel |
| US6436326B1 (en) | 1999-06-15 | 2002-08-20 | Dow Global Technologies Inc. | Forming slurry of reactive components and continuously feeding into continuous reactor |
| US20020180099A1 (en) * | 1999-06-15 | 2002-12-05 | Keillor Peter T. | Process and apparatus for preparing a composition using a slurry feed |
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